The Most Costly Lobster Dinner of the Summer.....
 

This afternoon I took my Four Winns Horizon 200 under the bridge in Wolfeboro to pick up some lobsters/steamers from Wolfe Catch. I was in the right center of the channel just past the town docks when my stern drive hit the bottom. Despite the headway speed and very slight bump, two of the prop blades were slightly curled (the lake level was 503.61' today). It never occurred to me that I would need to lift the stern drive to get into Back Bay....but now I know! Beware if you travel into Back Bay beyond the Town Docks!!

When back out in Wolfeboro Bay and at speed....there was no perceptible shimmy/shake and the boat ran at the same MPH at 3000 RPM as it always did....so is it OK to continue to run the boat on the damaged prop or could I be causing even greater problems than simply replacing the prop if I continue to use it without repairs??
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No. not ok.
 

The prop is balanced and although you do not feel anything you could be doing damage to your bearings or internal parts.
Be thankful you run an aluminum prop and not a stainless steel one.
I'd check around for a used repaired prop and send yours out, then you'll always have a spare.
On the last 3 boats I owned I've never not carried a spare prop.
Good luck.

Change it or send it out to be repaired or do both then you'll have a spare and never need it:laugh:

A new prop costs a heck of a lot less than a lower unit. Do you have a picture of the prop out of the water?

Looking at the prop blade on the upper right..If that is typical: Get a small flat file from the hardware store and "Dress It Up". No Biggy. You will be fine the rest of the season and maybe even next. Just my experience. A little nick or burr is of little consequence. File it and forget it. :D NB

You're on an island, you need a spare. Order one and a plastic floating prop wrench, yours will hold you until then. Afterwards send yours out for repair, it will be your spare.

Just my opinion.

Aluminum props are a few hundred at most. What does it cost for H&H to repair one these days? The one for my toon was $148 new.

You can just touch it up with a file if it still performs OK. The bearings in the lower unit can easily handle the miniscule amount of off-balance load caused by the damage. The bearings are the same style (tapered roller) and are of similar size used in car and trailer wheels. They are built for hugely unbalanced side loads.

I've been wanting to go to WolfeTrap by Coronado all summer, but was more concerned about my windshield than my prop! In your opinion is there enough depth/height for me to attempt it with an inboard?

There are a number old expensive antique and replica "Strait Inboards" home ported in Back Bay...including the "Millie B" Hackercraft (Replica) ride boat that works from the Wolfeboro town docks. I think she is 28 feet. :) NB

PS: In spite of the markers in the channel, "Local Knowledge" is a PLUS.

Agreed, we always have a spare on the island boat. Had to change one while at the island once, really was glad to have had the spare on board.

Your chance of dinging a prop on this lake is much greater than the chance of a flat on your vehicle. And you probably have a spare tire.

We have replaced two props on our i/o boat now. One hubby did, one I did recently in Boston Harbor not realizing how low, low tide was near the yacht club we now belong to. Now I know exactly which markers I need to follow no matter what the tide.

Anyhow, new prop for us thru West Marine was about $130 delivered. And we ran with the banged up one for about a month before replacing it, we waited until just before vacation last month in Alton to fix it. I also chewed up the straight peice below the prop (not sure of the name) that acts like a rudder. Hubby just made a form and bondo-ed and filed it.

But yours dosen't even look that bad, so I'd just order a spare and fix up that one where you do live on an island and getting to a store is not easy.

A lot of assumptions are being made after looking at only one blade of three. In order to be sure I would suggest all three blades be checked. Props are carefully made to be balanced. It doesn't take much to upset this balance.

The thingy that acts like a rudder is called a skeg.

The OP stated: "When back out in Wolfeboro Bay and at speed....there was no perceptible shimmy/shake and the boat ran at the same MPH at 3000 RPM as it always did". No assumptions required.

They're your boats. Do what you want. I am only trying to help.

Dave R is arguably the most knowledgable boater on this site. If he says you can run a slightly dinged prop as long as there is no vibration I'd go with his advice. I have listened to him many times in the past with excellent outcomes.

What has he helped you with? If it has anything to do with props it will be beneficial to us all.

What if he is wrong. My advise will cost you nothing. Other's advise might cost you a lower unit.

Take a few minutes and go through Dave R's historical advise and ask your boat mechanic about the prop question (I did) and you will see. You and I and many of the others on the board would likely switch a dinged prop as soon as possible. However, it's is inaccurate to tell someone that they are doing damage to the lower unit with a slightly dinged prop if no dedectable vibration is being dedected.

Honestly
 

Sometimes you site back and wish you said nothing and let Capt. ????? learn for themselves the hard way. :cool: :cool:
But if you honestly think that someone looking at a picture that shows only part of the damage can make an educated GUESS then I guess Dave R is a god. Granted Dave has had some excellent advice with respect to engine problems and boating matters but the cost to replace an outdrive is in excess of $2000.00 for a rebuilt unit. Do you really suggest someone who can afford a boat to begin with take a chance when they can have a part fixed for under $200. :eek:
I don't know for me it is a no brainer, fix the prop, but who am I, I have only been working on my own boats, cars, snowmobiles and ATV's for oh, 40 some years. I just don't offer advise on those subjects because if your wrong you get beat up bad on this forum. :rolleye2:
My advise, run it as is, if it breaks then you'll know you should have fixed the prop. Let us know though because if the prop does damage to lower unit it should make for an I told you so and a good laugh for some of us!!!!

If you have been boating a long time, chances are you know people that have hit rocks hard enough to shear huge chunks of a blades (or entire blades) off aluminum props without internally damaging the lower gear case or prop shaft on an Alpha drive. They just installed a new prop and kept boating. A gear case that can shrug off the violence of a hit like that is not going to be damaged by a fraction of an ounce (or even several ounces) of prop imbalance.

The big, tapered roller bearings that support the prop shaft can easily cope with unbalanced loads. Think about how unbalanced the loads are on a car wheel (that uses the same kind of bearings). There's probably 800 lbs or more of load pushing up on the bottom of the bearing on a typical car wheel, and -800 lbs at the top, when just rolling along straight and flat. Throw in some cornering, bumps, and braking and the loads can become huge. Those bearings usually last the lifetime of the car, even if they are neglected.

Put a brand-new new aluminum prop on a balance stand some time (I made one when I repaired and modified Alpha props years ago), they are rarely perfectly balanced. They don't need to be.

Thanks to all for your opinion & advice!!
 

I want to thank everyone who took the time to offer their opinion & advice on the damage done to my propeller. When the smoke cleared....given that I live on an island and wouldn't be able to use the summer home if I did significant damage to the stern drive/etc i opted to take the cautious approach: today I had a new prop installed and sent out the damaged prop for repairs (so that I'll have a back up on board). Thanks again!

AGAIN: Looking at your picture....you have NOTHING to worry about. Dress up the prop with a file and enjoy. You don't need a new prop. :) NB

Peace of mind AND a spare prop are valuable. Glad you have both now.